Improvement in cut-off valves and gears



l N. E..NASH" But-Off Valves and. Gears.

Patented Sept. 8,1874.

No.154g80 2.

WITNESSES.

UNITED-STATES PATENT OFFICE.

"NATHAN E. NASH, or wEsTERLY, RHODE ISLAND.

I IMPROVEMENT IN CUT-OFF VALVEs AND GEARS.

Specification forming part of Letters Patent No. 154,802, dated September 8, 1874 application filed March 17, 1874.

To all whom it may concern 'Be it known that I, NATHAN E. NAsH, of Westerly, in the county of Washington and State of Rhode Island, have invented certain Improvements in Out-Off Valves for Steam- Engines, of which the following is a specification; and I do hereby declare that in the same is contained a full, clear, and exact description of my said invention, reference beinghad to the accompanying drawing, and to the letters of reference marked thereon.

My invention relates to certain devices, hereinafter described, for transmitting motion to the valves of steam-engines, by means of which devices the point at which the steam is cut off during the stroke of the piston is made variable, and governed by the action of the governor; to certain modifications in the said steam and exhaust valves fitting them to be operated by means of the aforementioned motive devices; and to other features looking to the adjustment of the steam- *alves with refthe accompanying drawing, forming a part of this specification, and in which Figure 1 is a front elevation of an engine having my improvements thereupon; Fig. 2, an enlarged view of the exterior of the steamcylinder with attachments; Fig. 3, a view of a detached portion of the invention; and Fig. 4, a view of the interior of the steam-chest, the bonnet or cover being removed.

A is the steam-cylinder, and B the steamchest, provided with the bonnet or cover B. D is a plate bolted steam-tight to the face of the cylinder, and in which are the steam-ports E E and exhaust-ports F F. The ports E E and F F in the plate D correspond with the steam and exhaust passages in the cylinder, being merely a continuation of them. G is a shaft, situate centrally of the steam-chest, and fastened at the inner end to the exhaust-valve H. To the outer end of the shaft Gr is fitted a rock shaft, a, connected by means of the Wrist-pin b to the eccentric rod 0. The steamvalves are represented by I I, and in common with the exhaust-valve H bear against the outer ends.

the curved bars ff, which are pivoted tosa block, g, clamped to the rockshaft a, and notched at their extended ends to engage pro jecting-pins h h on the arms 0 e. K is a rod, susceptible of a vertical motion only, which. it receives from the engine-governor, which governor, as it forms no part of my invention, is not shown in the drawing. L L are slotted rods, pivoted to the rod K, the pins securing them to the rod passing through the said slots, allowing the said slotted rods to have considerable longitudinal movement. The rods L L are attached to the curved bars ff near their notched ends. The shafts G, d, and d, where they pass through the steam-chest bonnet B, are packed, the said'packing being held in position by the flange i.

The parts of my invention not yet alluded to will be duly considered as the operations of the different members constituting the machine are described.

The crank being at the center, as shown in Fig. 1, and the eccentric placed in such position with reference to the crank as to cause the shaft to revolve in the direction indicated by the arrow, steam from the steam chest passes through the port E, which has been partially uncovered, into the cylinder, causing the piston to move and the shaft to revolve. The valve 1 is now rapidly opened bymeans of the curved bar f, the movement in this direction continuing until the rock-shafta and bar f have reached their extreme limit, when a retrograde motion of the rock-shaft and bar takes place, and the valve is forced back to its original position by the spring 70. After the crank has passed the other center, the valve I is opened, and the piston moves in an oppositedirection.

The above description of the opening and closing of the valves is only applicable when the engine is working at "full stroke, or using steam from the steam-chest until the piston has reached the end of its stroke.

The steam is cut off by the action of the governor, raising the notches on the curved barsffi from the pins h h on the arms '6 e by means of the rod K and slotted rods L L, allowing the valves to be forced suddenly back and the ports closed by means of the springs k is. It will be understood that the point of cutting off is regulated only by the vertical height of the" rod K. The lead or opening given by the valves at the beginning of the stroke is regulated by the position of the adjustable block 9, to which the curved bars ff are pivoted, and which may be elevated or depressed to diminish or increase the lead, as. i

may be desired; but this adjustment may be accomplished automatically by attaching the movable block 9 by means of a system of levers and rods to the rod K, thereby increasing or diminishing the lead as the velocity of the piston is increased or diminished.

' By reference to Fig. 4, it will be observed that the interior of the exhaust-va1ve is at all times in communication with the outlet-pipe M.

Having thus described my inventiomwhat I claim as new, and desire to secure by Letters Patent of the United States, is-- 1. The valves 1,1", and H, withtheir respective shafts, incombination with the bars f, rods L L, and vertical rod K, rock-shaft a and arms 0 c, with their pins h h, the whole constituting a valve-gear, causing the point of cutting of the steam to be variable and con sequent upon the movement of the governor transmitted through the medium of the said rod K, substantially as specified.

2. The vertically-adjustable block 1, in combination with the rock-shaft a and bars ff, as and for the purpose set forth.

3. The plate 1), bolted to the face of the cylinder, and inclosed within the steam-chest, and having steam and exhaust ports correspending with those in the cylinder and out let-pipe M, in combination with the steamvalves I I and exhaust-valve H, operated by and upon their respective shafts, substantially as specified.

In testimony whereof I have hereunto subscribed my name.

NATHAN E. NASH. Witnesses:

GEORGE H. HOWARD, THOMAS C. GoNNoLLY. 

